1. Field
The present subject matter relates generally to the field of fast optical filters, whose operation is wavelength dependent, especially for use as a wavelength selective device in an optical communication system.
2. Description of the Related Art
It is known in optical communications systems to use wavelengths as optical carriers for carrying digital or analog information. Also, the different wavelengths may be used to discriminate one set or channel of information from another. When a plurality of wavelengths are coupled or multiplexed onto a single fiber, this is called wavelength division multiplexing (WDM). Use of such WDM increases the overall bandwidth of the system.
There is a need in such systems to switch packets of optical information passing along one fiber to any of a number of other fibers, according to the wavelength of the optical signal. Such a switch is known as an optical filter or a wavelength selective device. A number of wavelength dependent filters have been developed using various characteristics of optical elements. There exists a need for a new optical, multi-pole, multi-way wavelength selective switch structure having a simple optical structure.